Wash and peel your chosen zucchini.
Cut the zucchini into 1/2" cubes (or whatever shape you prefer) to imitate canned pineapple.
Prepare the jars so that they are clean and hot by the time your zucchini will be done.
Prepare your water bath canner so that it is at a simmer for when your hot mock pineapple is ready.
In a large pot, combine the pineapple juice, lemon juice, and sugar.
Add the zucchini cubes to the juice mixture and bring the mixture to a boil, stirring every few minutes.
Once boiling, reduce to a simmer for 20 minutes, stirring every few minutes.
Using a ladle or large measuring cup, pour the cooked mock pineapple into hot jars.
Top the jars with the hot pineapple juice leaving 1/2-inch headspace.
Use a chopstick or butter knife to remove air bubbles.
Dampen a clean cloth with white vinegar to wipe the rims of the mock pineapple jars.
Place lids on the jars and screw on the bands just until fingertip tight.
Place the hot jars on the canning rack in a boiling water bath.
Ensure jars are covered by 1-2 inches of water.
Process for 15 minutes.
Turn off the stove and allow the jars to remain in the canner for 5 minutes before removing them.
Remove jars from the water bath canner and allow them to cool on a clean towel or dish mat undisturbed for 12-24 hours.
Press the center of each lid to ensure it is sealed properly. If the lid pops back, the jar did not seal and should be refrigerated (use within 7 days).
Label jars with the date and contents.
Store in a cool, dark place.
Enjoy!